<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>

<body>
    <script>
        // 接口地址:https://api.apiopen.top/getJoke

        const p = new Promise((resolve, reject) => {
            //1.创建对象
            const xhr = new XMLHttpRequest();

            //2.初始化
            xhr.open('GET', 'https://api.apiopen.top/getJoke');

            //3.发送
            xhr.send();

            //4.绑定事件,处理响应结果
            xhr.onreadystatechange = function() {
                //判断 响应状态码 200-299
                if (xhr.status >= 200 && xhr.status < 300) {
                    //表示成功
                    resolve(xhr.response);
                } else {
                    //如果失败
                    reject(xhr.status);
                };
            };
        });

        //指定回调
        p.then(function(value) {
            console.log(value);
        }, function(reason) {
            console.log(reason);
        })
    </script>
</body>

</html>